Lifetime medical costs of knee osteoarthritis management in the United States: impact of extending indications for total knee arthroplasty

A randomized, controlled study to evaluate the efficacy of intra-articular, autologous adipose tissue injections for the treatment of mild-to-moderate knee osteoarthritis compared to hyaluronic acid: a study protocol

BACKGROUND

Osteoarthritis (OA) is a highly debilitating joint disease that causes progressive, irreversible damage to articular cartilage. OA takes a massive toll on society that has grown in recent decades, but no therapy has been shown to halt or reverse the progression of the disease. The critical need for better treatments and increased interest cellular therapies has spawned a new generation of "minimally manipulated" cell treatments. Autologous adipose tissue injections are among the most controversial of these new treatments. Despite a lack of clinical evidence, adipose tissue injections are often marketed as "stem cell" injections with wide-ranging regenerative benefits. The purpose of this study is to estimate the effect size of the treatment by comparing the efficacy of autologous fat to hyaluronic acid (HA). As a secondary aim, we will test for preliminary evidence of efficacy of autologous fat vs. HA.

METHODS

This is a prospective, single-center, parallel-group, randomized, controlled trial. Participants (n = 54) will receive either a single intra-articular, ultrasound-guided injection of autologous adipose tissue or a single intra-articular, ultrasound-guided injection of HA (1:1 ratio). Outcome data will be obtained at baseline, week-6 and month-6. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain domain (WOMAC-A) will be used as the primary outcome measure. Secondary clinical outcome measures include WOMAC (full), clinical anchors (pain, function, and stiffness), and the 29-point Patient-Reported Outcomes Measurement Information System (PROMIS®) profile. We will also take synovial fluid samples and assess sway velocity using a force plate, as well as analyze excess/discard adipose tissue to gain a better understanding of how intra-articular adipose tissue injections influence the biochemical environment of the joint.

DISCUSSION

Given the widespread use of intra-articular fat injections in the United States, it is critical that randomized, controlled human studies evaluating efficacy and biological activity be performed. This study is the first step in addressing this unmet need, but it is not without limitations. The most notable limitations of this study are its small size and lack of blinding, which predisposes the study to both investigator and participant bias.

TRIAL REGISTRATION

NCT03242707 // HS-17-00365 // Registration Date (First Posted): August 8, 2018.

Relationship between ADAMTS14/rs4747096 gene polymorphism and knee osteoarthritis in Chinese population

To investigate the association between single nucleotide polymorphisms (SNPs) of A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 14 (ADAMTS14) gene and susceptibility to knee osteoarthritis (KOA) in Chinese Han population. Using a case–control design, we enrolled 346 KOA patients and 480 healthy controls. Peripheral blood samples were extracted from each subject. Genotype was determined by sequencing PCR products. The genotype frequencies between cases and controls were compared. The genotype distribution was in accordance with Hardy–Weinberg equilibrium. The minor G allele in case group was significantly higher than in the control group (21.4 compared with 8.8%, P=0.000, odds ratio (OR) = 1.71 (95% confidence interval (CI): 1.39–2.11). The GG genotype and the GG/AG combination were more common in the osteoarthritis (OA) group than in the control group. Compared with AA genotype, the GG (OR = 3.09, 95%CI: 2.01–4.75), AG (OR = 2.55, 95%CI: 1.64–3.96), and GG/AG (OR = 1.57, 95%CI: 1.19–2.07) increased the risk of OA. Multiple logistic confirmed the findings by adjusting some potential factors. Subgroup analysis indicated that the ras4747096 was still significantly associated with KOA. There were no significant differences in allele frequency or genotypes frequency for erythrocyte sedimentation rate and C-reaction protein in OA patients (P>0.05). ADAMTS14 gene polymorphism was associated with KOA, and the GG genotype increased the risk of KOA in Chinese Han population. The ADAMTS14 may be a diagnostic marker and therapeutic target for KOA treatment. The future study should explore the specific molecular mechanism.

Development and validation of prediction models to estimate risk of primary total hip and knee replacements using data from the UK: two prospective open cohorts using the UK Clinical Practice Research Datalink

Objectives

The ability to efficiently and accurately predict future risk of primary total hip and knee replacement (THR/TKR) in earlier stages of osteoarthritis (OA) has potentially important applications. We aimed to develop and validate two models to estimate an individual’s risk of primary THR and TKR in patients newly presenting to primary care.

Methods

We identified two cohorts of patients aged ≥40 years newly consulting hip pain/OA and knee pain/OA in the Clinical Practice Research Datalink. Candidate predictors were identified by systematic review, novel hypothesis-free ‘Record-Wide Association Study’ with replication, and panel consensus. Cox proportional hazards models accounting for competing risk of death were applied to derive risk algorithms for THR and TKR. Internal–external cross-validation (IECV) was then applied over geographical regions to validate two models.

Results

45 predictors for THR and 53 for TKR were identified, reviewed and selected by the panel. 301 052 and 416 030 patients newly consulting between 1992 and 2015 were identified in the hip and knee cohorts, respectively (median follow-up 6 years). The resultant model C-statistics is 0.73 (0.72, 0.73) and 0.79 (0.78, 0.79) for THR (with 20 predictors) and TKR model (with 24 predictors), respectively. The IECV C-statistics ranged between 0.70–0.74 (THR model) and 0.76–0.82 (TKR model); the IECV calibration slope ranged between 0.93–1.07 (THR model) and 0.92–1.12 (TKR model).

Conclusions

Two prediction models with good discrimination and calibration that estimate individuals’ risk of THR and TKR have been developed and validated in large-scale, nationally representative data, and are readily automated in electronic patient records.

Cost-Effectiveness of Surgical and Nonsurgical Treatments for Unicompartmental Knee Arthritis: A Markov Model

BACKGROUND

There has been increased utilization of surgical options for the treatment of end-stage unicompartmental arthritis in patients at both extremes of the age spectrum. The purpose of this study was to determine how these changing paradigms affected the lifetime cost-effectiveness of total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), and nonsurgical treatment (NST).

METHODS

Using a Markov decision analytic model, we assessed how lifetime costs and quality-adjusted life years (QALYs) vary as a function of age at the time of initial treatment (ATIT) of patients with end-stage unicompartmental knee osteoarthritis undergoing TKA, UKA, and NST. Separate models were estimated for ATITs at 5-year intervals from 40 through 90 years. Direct medical costs, QALYs, and transition probabilities were determined from the published literature. Indirect costs (lost wages, Social Security disability collections, and value of missed workdays) were calculated. Cost-effectiveness and incremental cost-effectiveness ratios (ICERs) were calculated for each treatment at each ATIT. The model assumed no crossover from NST to UKA or TKA. ICERs were compared with a willingness-to-pay threshold of 50,000 U.S. dollars, and a 1-way sensitivity analysis was used to assess the robustness of ICER-based treatment decisions. Societal savings were estimated.

RESULTS

In the base-case model, surgical treatments were less expensive and provided a greater number of QALYs than NST from 40 to 69 years of age. From 70 years of age and onward, surgical treatments remained cost-effective compared with NST, with ICERs remaining below the societal willingness-to-pay threshold. When surgical treatments were compared, UKA dominated TKA for all ATITs. The preferential use of UKA in all U.S. patients with unicompartmental osteoarthritis would result in an estimated lifetime societal savings of 987 million to 1.5 billion U.S. dollars per annual wave of patients undergoing treatment.

CONCLUSIONS

In this preliminary assessment, recent expansion of surgical treatments into younger and older age demographics appears to be cost-effective in the setting of unicompartmental knee osteoarthritis. Our findings suggest that NST should be used sparingly in patients below the age of 70 years and UKA should be chosen over TKA in order to maximize cost-effectiveness.

LEVEL OF EVIDENCE

Economic and decision analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Regenerative medicine will make orthopaedic implants obsolete in our time Orthopaedic Research Society first annual meeting debate, San Diego, March 21st, 2017

The mission of the Orthopaedic Research Society is to promote and advance musculoskeletal research worldwide. With this in mind, the Annual Meeting Program Committee sought to establish a debate as a key component of the meeting. Our purpose was to provoke discussion on topics that are core to our mission and to engage all constituencies within the society by examining questions of broad relevance. To this end, the topic "Regenerative medicine will make orthopaedic implants obsolete in our time" was selected as the title of the inaugural debate. The arguments for and against the motion are presented in this perspectives article. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2579-2585, 2018.

Disparities in Total Knee Replacement: Population Losses in Quality-Adjusted Life-Years Due to Differential Offer, Acceptance, and Complication Rates for African Americans

OBJECTIVE

Total knee replacement (TKR) is an effective treatment for end-stage knee osteoarthritis (OA). American racial minorities undergo fewer TKRs than whites. We estimated quality-adjusted life-years (QALYs) lost for African American knee OA patients due to differences in TKR offer, acceptance, and complication rates.

METHODS

We used the Osteoarthritis Policy Model, a computer simulation of knee OA, to predict QALY outcomes for African American and white knee OA patients with and without TKR. We estimated per-person QALYs gained from TKR as the difference between QALYs with current TKR use and QALYs when no TKR was performed. We estimated average, per-person QALY losses in African Americans as the difference between QALYs gained with white rates of TKR and QALYs gained with African American rates of TKR. We calculated population-level QALY losses by multiplying per-person QALY losses by the number of persons with advanced knee OA. Finally, we estimated QALYs lost specifically due to lower TKR offer and acceptance rates and higher rates of complications among African American knee OA patients.

RESULTS

African American men and women gain 64,100 QALYs from current TKR use. With white offer and complications rates, they would gain an additional 72,000 QALYs. Because these additional gains are unrealized, we call this a loss of 72,000 QALYs. African Americans lose 67,500 QALYs because of lower offer rates, 15,800 QALYs because of lower acceptance rates, and 2,600 QALYs because of higher complication rates.

CONCLUSION

African Americans lose 72,000 QALYs due to disparities in TKR offer and complication rates. Programs to decrease disparities in TKR use are urgently needed.

Patients Less Likely to Lose Weight Following a Knee Replacement: Results From the Osteoarthritis Initiative

BACKGROUND

Knee replacement typically results in reduced pain and improved function, but it is unclear if these improvements lead to weight loss.

OBJECTIVE

The purpose of this study was to examine weight change patterns preoperatively and postoperatively among overweight/obese knee replacement patients.

METHODS

The study evaluated 210 overweight/obese patients from the Osteoarthritis Initiative who underwent a knee replacement during an 8-year longitudinal study. Average annual weight changes during 1- to 2-year intervals prior to, including, and subsequent to knee replacement were categorized as loss (≥-2.5%), maintain (>-2.5% to <2.5%), and gain (≥2.5%). Weight changes across time intervals were compared using logistic regression with generalized estimating equations, adjusting for demographic, health, and knee factors.

RESULTS

On average, patients lost -0.6 kg/y during the interval when the surgery was performed, but weight gain (0.9 kg/y) in the initial postoperative interval represented an overall net weight gain (0.3 kg/y) compared with presurgery. Continued weight gain (0.3 kg/y) was also seen among patients with additional follow-ups. Patients were significantly less likely to have a meaningful weight loss in the time interval immediately following the surgery compared with the interval in which the surgery took place (odds ratio, 0.37; 95% confidence interval, 0.18-0.79).

CONCLUSIONS

Overweight and obese patients initially lost weight during the interval including knee replacement; however, they were less likely to lose more than 2.5% of their weight in the 1 to 2 years immediately after the surgery. Knee replacement patients may benefit from weight management interventions both preoperatively and postoperatively.

The Cost-Effectiveness of Total Hip Arthroplasty in Patients 80 Years of Age and Older

BACKGROUND

This study investigates the cost-effectiveness of total hip arthroplasty (THA) in patients 80 years old.

METHODS

A Markov, state-transition model projecting lifetime costs and quality-adjusted life years (QALYs) was constructed to determine cost-effectiveness from a societal perspective. Costs (in 2016 US dollars), health state utilities, and state transition probabilities were obtained from published literature. Primary outcome was incremental cost-effectiveness ratio, with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to evaluate parameter assumptions.

RESULTS

At our base-case values, THA was cost-effective compared to non-operative treatment with a total lifetime accrued cost of $186,444 vs $182,732, and a higher lifetime accrued utility (5.60 vs 5.09). Cost per QALY for THA was $33,318 vs $35,914 for non-operative management, and the incremental cost-effectiveness ratio was $7307 per QALY. Sensitivity analysis demonstrated THA to be cost-effective with a utility of successful primary THA above 0.67, a peri-operative mortality risk below 0.14, and a risk of primary THA failure below 0.14. Analysis further demonstrated that THA is a cost-effective option below a base-rate mortality threshold of 0.19, corresponding to the average base-rate mortality of a 93-year-old individual. Markov cohort analysis indicated that for patients undergoing THA at age 80 there was an approximate 28% reduction in total lifetime long-term assisted living expenditure compared to non-operatively managed patients with end-stage hip osteoarthritis.

CONCLUSION

The results of our model demonstrate that THA is a cost-effective option compared to non-operative management in patients ≥80 years old. This analysis may inform policy regarding THA in elderly patients.

Understanding the Relationship Between 3-Month and 2-Year Pain and Function Scores After Total Knee Arthroplasty for Osteoarthritis

BACKGROUND

Research to understand predictors of poor outcomes after total knee arthroplasty (TKA) has largely focused on presurgery factors. We examined whether pain and function 3-month postsurgery were predictive of longer-term outcomes ascertained 2 years after TKA.

METHODS

Western Ontario McMaster University Osteoarthritis Index pain and physical function scores (scaled 0-20 and 0-68; higher = worse) were recorded pre-TKA and 3, 12, and 24 months post-TKA. A sequential series of regression models was used to examine the relative contribution of baseline score and baseline to 3-month and 3 to 12-month change score to explaining variability (R²) in 2-year pain and function scores, with consideration for presurgery covariates.

RESULTS

Data from 560 patients were analyzed. Mean pain and function scores improved significantly presurgery to 2 years postsurgery; 10-4 and 33-16 (P < .001), respectively. Considerable variability in 2-year scores was observed. Overall, 80.3% and 79.9% of changes in pain and function scores over the 2 years occurred within the first 3 months. Change over these 3 months explained the greatest proportion of variability in 2-year scores, 16% and 23% for pain and function, respectively. The influences of these early changes were similar to those of baseline status.

CONCLUSION

Changes in patient-reported pain and function occurring within the first 3 months post-TKA strongly determine pain and function status at 2 years. Research to identify pre-/intra-/early postoperative factors associated with change in this early postoperative period that may be amenable to modification or used to better inform education and decision-making is warranted.

Cost-effectiveness of generic celecoxib in knee osteoarthritis for average-risk patients: a model-based evaluation

OBJECTIVE

The cost-effectiveness of the recently-introduced generic celecoxib in knee OA has not been examined.

METHOD

We used the Osteoarthritis Policy (OAPol) Model, a validated computer simulation of knee OA, to evaluate long-term clinical outcomes, costs, and cost-effectiveness of generic celecoxib in persons with knee OA. We examined eight treatment strategies consisting of generic celecoxib, over-the-counter (OTC) naproxen, or prescription naproxen, with or without prescription or OTC proton-pump-inhibitors (PPIs) to reduce gastrointestinal (GI) toxicity. In the base case, we assumed that annual cost was $130 for OTC naproxen, $360 for prescription naproxen, and $880 for generic celecoxib. We considered a willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY) and discounted costs and benefits at 3% annually. In sensitivity analyses we varied celecoxib toxicity, discontinuation, cost, and pain level.

RESULTS

In the base case analysis of the high pain cohort (WOMAC 50), celecoxib had an incremental cost-effectiveness ratio (ICER) of $284,630/QALY compared with OTC naproxen. Only under highly favorable cost, toxicity, and discontinuation assumptions (e.g., annual cost below $360, combined with a reduction in the cardiovascular (CV) event rates below baseline values) was celecoxib likely to be cost-effective. Celecoxib might also be cost-effective at an annual cost of $600 if CV toxicity were eliminated completely. In subjects with moderate pain (WOMAC 30), at the base case CV event rate of 0.2%, generic celecoxib was only cost-effective at the lowest plausible cost ($190).

CONCLUSION

In knee OA patients with no comorbidities, generic celecoxib is not cost-effective at its current price.

Financial Incentives and Health Coaching to Improve Physical Activity Following Total Knee Replacement: A Randomized Controlled Trial

OBJECTIVE

Most persons who undergo total knee replacement (TKR) do not increase their physical activity following surgery. We assessed whether financial incentives and health coaching would improve physical activity in persons undergoing TKR.

METHODS

We designed a factorial randomized controlled trial among persons undergoing TKR for osteoarthritis. Subjects underwent normal perioperative procedures, including postoperative physical therapy, and were assigned to 1 of 4 arms: attention control, telephonic health coaching (THC), financial incentives (FI), or THC + FI. We objectively measured step counts and minutes of physical activity using a commercial accelerometer (Fitbit Zip) and compared the changes from pre-TKR to 6 months post-TKR across the 4 study arms.

RESULTS

Of the 202 randomized subjects, 150 (74%) provided both pre-TKR and 6 months post-TKR accelerometer data. Among completers, the mean ± SE daily step count at 6 months ranged from 5,619 ± 381 in the THC arm to 7,152 ± 407 in the THC + FI arm (adjusting for baseline values). Daily step count 6 months post-TKR increased by 680 (95% confidence interval [95% CI] -94, 1,454) in the control arm, 274 (95% CI -473, 1,021) in the THC arm, 826 (95% CI 89, 1,563) in the FI arm, and 1,808 (95% CI 1,010, 2,606) in the THC + FI arm. Weekly physical activity increased by mean ± SE 14 ± 10, 14 ± 10, 16 ± 10, and 39 ± 11 minutes in the control, THC, FI, and THC + FI arms, respectively.

CONCLUSION

A dual THC + FI intervention led to substantial improvements in step count and physical activity following TKR.

Telephone-based weight loss support for patients with knee osteoarthritis: a pragmatic randomised controlled trial

OBJECTIVE

To determine the effectiveness of telephone-based weight loss support in reducing the intensity of knee pain in patients with knee osteoarthritis, who are overweight or obese, compared to usual care.

DESIGN

We conducted a parallel randomised controlled trial (RCT), embedded within a cohort multiple RCT of patients on a waiting list for outpatient orthopaedic consultation at a tertiary referral hospital in NSW, Australia. Patients with knee osteoarthritis, classified as overweight or obese [body mass index (BMI) between ≥27 kg/m² and <40 kg/m²] were randomly allocated to receive referral to an existing non-disease specific government funded 6-month telephone-based weight management and healthy lifestyle service or usual care. The primary outcome was knee pain intensity measured using an 11-point numerical rating scale (NRS) over 6-month follow-up. A number of secondary outcomes, including self-reported weight were measured. Data analysis was by intention-to-treat according to a pre-published analysis plan.

RESULTS

Between May 19 and June 30 2015, 120 patients were randomly assigned to the intervention (59 analysed, one post-randomisation exclusion) or usual care (60 analysed). We found no statistically significant between group differences in pain intensity [area under the curve (AUC), mean difference 5.4, 95%CI: -13.7 to 24.5, P = 0.58] or weight change at 6 months (self-reported; mean difference -0.4, 95%CI: -2.6 to 1.8, P = 0.74).

CONCLUSIONS

Among patients with knee osteoarthritis who are overweight, telephone-based weight loss support, provided using an existing 6-month weight management and healthy lifestyle service did not reduce knee pain intensity or weight, compared with usual care.

TRIAL REGISTRATION NUMBER

ACTRN12615000490572.

Effectiveness of Valgus Offloading Knee Braces in the Treatment of Medial Compartment Knee Osteoarthritis: A Systematic Review

CONTEXT:

Knee osteoarthritis affects 9.3 million adults over age 45 years in the United States. There is significant disability associated with this condition. Given the potential complications and the significant cost to the health care system with the dramatic increase in total knee arthroplasties performed for this condition, assessment of the efficacy of nonoperative modalities, such as offloading knee braces, is essential as part of optimizing nonoperative treatment for this condition.

OBJECTIVE:

To determine the effectiveness of valgus offloader braces in improving clinical outcomes for patients with medial compartment knee osteoarthritis.

DATA SOURCES:

Three databases (PubMed, MEDLINE, and EMBASE) were searched from database inception through July 28, 2017.

STUDY SELECTION:

Studies reporting outcomes of valgus offloader knee braces in the treatment of medial compartment knee osteoarthritis were included.

STUDY DESIGN:

Systematic review.

LEVEL OF EVIDENCE:

Level 4.

DATA EXTRACTION:

Data pertaining to demographics, descriptive statistics, and clinical outcomes were extracted from the included studies. The methodological quality of included studies was evaluated.

RESULTS:

A total of 31 studies were included, with a total of 619 patients. The majority of studies reported improved pain outcomes using valgus offloader braces. However, variable results were reported as to whether valgus offloader braces significantly improved functional outcomes and stiffness. Offloader bracing was more effective at reducing pain when compared with neutral braces or neoprene sleeves.

CONCLUSION:

Valgus offloader bracing is an effective treatment for improving pain secondary to medial compartment knee osteoarthritis. The literature remains unclear on the effectiveness of valgus offloader braces with regard to functional outcomes and stiffness. Larger prospective randomized trials with consistent outcome assessment tools and consideration of patient compliance would be beneficial to more accurately determine treatment effects of valgus offloader bracing.

Musculoskeletal pain and menopause

Musculoskeletal pain, arthralgia and arthritis are all more common in women, and their frequency increases with age and in some appears to be associated with the onset of menopause. The clinical assessment, investigation and management of women presenting with musculoskeletal pain, arthralgia or arthritis at the time of menopause are reviewed. Common causes of arthralgia and arthritis in this population are discussed. The epidemiological and trials evidence for the effects of hormone replacement therapy on musculoskeletal pain and arthritis (primarily from RCTs of HRT for other menopausal symptoms) are discussed. Lastly, the possible underlying aetiological roles of sex hormones including estrogen, and their deficiency, in predisposing to musculoskeletal pain and arthritis are overviewed. Although the association appears strong, a causal link between estrogen deficiency and musculoskeletal pain or different types of arthritis is lacking; there have been few studies specifically within this group of symptomatic patients, and there is much still to understand about musculoskeletal pain and arthritis at the time of the menopause, and about how we might prevent or treat this.

Quantitative sodium MR imaging: A review of its evolving role in medicine

Sodium magnetic resonance (MR) imaging in humans has promised metabolic information that can improve medical management in important diseases. This technology has yet to find a role in clinical practice, lagging proton MR imaging by decades. This review covers the literature that demonstrates that this delay is explained by initial challenges of low sensitivity at low magnetic fields and the limited performance of gradients and electronics available in the 1980s. These constraints were removed by the introduction of 3T and now ultrahigh (≥7T) magnetic field scanners with superior gradients and electronics for proton MR imaging. New projection pulse sequence designs have greatly improved sodium acquisition efficiency. The increased field strength has provided the expected increased sensitivity to achieve resolutions acceptable for metabolic interpretation even in small target tissues. Consistency of quantification of the sodium MR image to provide metabolic parametric maps has been demonstrated by several different pulse sequences and calibration procedures. The vital roles of sodium ion in membrane transport and the extracellular matrix will be reviewed to indicate the broad opportunities that now exist for clinical sodium MR imaging. The final challenge is for the technology to be supplied on clinical ≥3T scanners.

Are bisphosphonates efficacious in knee osteoarthritis? A meta-analysis of randomized controlled trials

OBJECTIVE

To clarify the effects of bisphosphonates in knee osteoarthritis (OA) using an up-to-date meta-analysis of randomized controlled trials (RCTs).

DESIGN

The protocol is registered in PROSPERO (CRD42017073449). We searched MEDLINE, EMBASE, Google Scholar, Web of Science, and Cochrane Database from inception until August 2017. We included only RCTs comparing any bisphosphonates vs placebo in knee OA patients and reporting validated pain and function scales, radiographic progression, and adverse events (AEs) outcomes. We excluded studies using active comparators or concomitant medications besides non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. We calculated standardized mean differences (SMDs) to account for variation in outcome scales. Random effects meta-analyses were performed.

RESULTS

We included seven RCTs (3013 patients, 69% female); most patients (N = 2767) received oral risedronate. No pain or function outcomes, regardless of dose, route, time point or measuring instrument, revealed statistically significant results (end of trial pain SMD = -0.16 [95% confidence interval (CI): -0.34, 0.02]). Similarly, we found no statistically significant effect on radiographic progression (risk ratio = 0.98 [95% CI: 0.77, 1.26]). One small RCT in patients with bone marrow lesions (BMLs) suggested a reduction in BML size at 6 months. Bisphosphonates displayed good tolerability, with no statistically significant differences in AE outcomes vs placebo.

CONCLUSIONS

Contrary to prior reviews, our analysis showed that bisphosphonates neither provide symptomatic relief nor defer radiographic progression in knee OA. However, these agents may still be beneficial in certain subsets of patients who display high rates of subchondral bone turnover. Future studies should be directed at defining such OA subsets and investigating the effects of bisphosphonates in those patients.

Tissue material properties and computational modelling of the human tibiofemoral joint: a critical review

Understanding how structural and functional alterations of individual tissues impact on whole-joint function is challenging, particularly in humans where direct invasive experimentation is difficult. Finite element (FE) computational models produce quantitative predictions of the mechanical and physiological behaviour of multiple tissues simultaneously, thereby providing a means to study changes that occur through healthy ageing and disease such as osteoarthritis (OA). As a result, significant research investment has been placed in developing such models of the human knee. Previous work has highlighted that model predictions are highly sensitive to the various inputs used to build them, particularly the mathematical definition of material properties of biological tissues. The goal of this systematic review is two-fold. First, we provide a comprehensive summation and evaluation of existing linear elastic material property data for human tibiofemoral joint tissues, tabulating numerical values as a reference resource for future studies. Second, we review efforts to model tibiofemoral joint mechanical behaviour through FE modelling with particular focus on how studies have sourced tissue material properties. The last decade has seen a renaissance in material testing fuelled by development of a variety of new engineering techniques that allow the mechanical behaviour of both soft and hard tissues to be characterised at a spectrum of scales from nano- to bulk tissue level. As a result, there now exists an extremely broad range of published values for human tibiofemoral joint tissues. However, our systematic review highlights gaps and ambiguities that mean quantitative understanding of how tissue material properties alter with age and OA is limited. It is therefore currently challenging to construct FE models of the knee that are truly representative of a specific age or disease-state. Consequently, recent tibiofemoral joint FE models have been highly generic in terms of material properties even relying on non-human data from multiple species. We highlight this by critically evaluating current ability to quantitatively compare and model (1) young and old and (2) healthy and OA human tibiofemoral joints. We suggest that future research into both healthy and diseased knee function will benefit greatly from a subject- or cohort-specific approach in which FE models are constructed using material properties, medical imagery and loading data from cohorts with consistent demographics and/or disease states.

Additive effect of tDCS combined with Peripheral Electrical Stimulation to an exercise program in pain control in knee osteoarthritis: study protocol for a randomized controlled trial

BACKGROUND

Knee osteoarthritis (OA) has been linked to maladaptive plasticity in the brain, which may contribute to chronic pain. Neuromodulatory approaches, such as Transcranial Direct Current Stimulation (tDCS) and Peripheral Electrical Stimulation (PES), have been used therapeutically to counteract brain maladaptive plasticity. However, it is currently unclear whether these neuromodulatory techniques enhance the benefits of exercise when administered together. Therefore, this protocol aims to investigate whether the addition of tDCS combined or not with PES enhances the effects of a land-based strengthening exercise program in patients with knee OA.

METHODS

Patients with knee OA (n = 80) will undertake a structured exercise program for five consecutive days. In addition, they will be randomized into four subgroups receiving either active anodal tDCS and sham PES (group 1; n = 20), sham tDCS and active PES (group 2, n = 20), sham tDCS and PES (group 3, n = 20), or active tDCS and PES (group 4, n = 20) for 20 min/day for five consecutive days just prior to commencement of the exercise program. The primary outcomes will be subjective pain intensity (VAS) and related function (WOMAC). Secondary outcomes will include quality of life (SF-36), anxiety and depression symptoms (HAD), self-perception of improvement, pressure pain thresholds over the knee, quadriceps strength, and quadriceps electromyographic activity during maximum knee extension voluntary contraction. We will also investigate cortical excitability using transcranial magnetic stimulation. Outcome measures will be assessed at baseline, 1 month after, before any intervention, after 5 days of intervention, and at 1 month post exercise intervention.

DISCUSSION

The motor cortex becomes less responsive in knee OA because of poorly adapted plastic changes, which can impede exercise therapy benefits. Adding tDCS and/or PES may help to counteract those maladaptive plastic changes and improve the benefits of exercises, and the combination of both neuromodulatory techniques must have a higher magnitude of effect.

TRIAL REGISTRATION

Brazilian Registry on Clinical Trials (ReBEC) - Effects of electrical stimulation over the skull and tight together with exercises for knee OA; protocol number RBR-9D7C7B.

TRIAL REGISTRATION

ID: RBR-9D7C7B . Registered on 29 February 2016.

A Fresh Perspective on a Familiar Problem: Examining Disparities in Knee Osteoarthritis Using a Markov Model

Supplemental Digital Content is available in the text.

Background:

Disparities in the presentation of knee osteoarthritis (OA) and in the utilization of treatment across sex, racial, and ethnic groups in the United States are well documented.

Objectives:

We used a Markov model to calculate lifetime costs of knee OA treatment. We then used the model results to compute costs of disparities in treatment by race, ethnicity, sex, and socioeconomic status.

Research Design:

We used the literature to construct a Markov Model of knee OA and publicly available data to create the model parameters and patient populations of interest. An expert panel of physicians, who treated a large number of patients with knee OA, constructed treatment pathways. Direct costs were based on the literature and indirect costs were derived from the Medical Expenditure Panel Survey.

Results:

We found that failing to obtain effective treatment increased costs and limited benefits for all groups. Delaying treatment imposed a greater cost across all groups and decreased benefits. Lost income because of lower labor market productivity comprised a substantial proportion of the lifetime costs of knee OA. Population simulations demonstrated that as the diversity of the US population increases, the societal costs of racial and ethnic disparities in treatment utilization for knee OA will increase.

Conclusions:

Our results show that disparities in treatment of knee OA are costly. All stakeholders involved in treatment decisions for knee OA patients should consider costs associated with delaying and forgoing treatment, especially for disadvantaged populations. Such decisions may lead to higher costs and worse health outcomes.

Is a high tibial osteotomy (HTO) superior to non-surgical treatment in patients with varus malaligned medial knee osteoarthritis (OA)? A propensity matched study using 2 randomized controlled trial (RCT) datasets

OBJECTIVE

No randomized controlled trial (RCT) has compared the high tibial osteotomy (HTO) with non-surgical treatment in patients with medial knee osteoarthritis (OA) and varus malalignment. The aim was to compare the effectiveness of an unloader brace treatment or a usual care program to the HTO regarding pain severity and knee function.

DESIGN

Surgical treatment (HTO) to two non-surgical options was compared by combining the data of two RCTs. One RCT (n = 117) compared an unloader brace to usual care treatment; the other RCT (n = 92) compared closing to opening wedge HTO. One-to-many propensity score matching was used to equalize patient characteristics. We compared clinical outcome at 1 year follow-up (VAS pain (0-10) and knee function (HSS, 0-100)) with mixed model analysis.

RESULTS

Propensity score matching resulted in a comparison of 30 brace patient with 83 HTO patients, and of 28 usual care patients with 71 HTO patients. Pain at 1 year after HTO (VAS 3.8) was lower than after valgus bracing (VAS 5.0) with a mean difference of -1.1 (95% CI -2.2; -0.1). Function showed a nonsignificant mean difference of 2.1 [95% CI -3.1; 7.3]. Comparing HTO to usual care a difference was seen in pain (-1.7 [95% CI -2.8; -0.6]) and function (6.6 [95% CI 0.2; 13.1]), in favor of the HTO.

CONCLUSIONS

Our data suggest that HTO was more effective in pain reduction compared to both non-surgical treatments. Function improved only when HTO was compared to usual care treatment. These small differences question the benefits of surgical treatment over the brace treatment.

Changes in biomechanical risk factors for knee osteoarthritis and their association with 5-year clinically important improvement after limb realignment surgery

OBJECTIVE

To evaluate 5-year outcomes after lower limb realignment and test the hypothesis that surgery-induced changes in selected biomechanical risk factors for medial knee osteoarthritis (OA) are associated with clinically important improvements.

DESIGN

We prospectively evaluated patient-reported outcomes, full-limb standing radiographs and gait biomechanics before, 6 months (surgery-induced change) and 5 years after medial opening wedge high tibial osteotomy (HTO) in 170 patients (46.4 ± 8.9 years, 135 males) with knee OA and varus alignment. Logistic regression tested the associations of 6-month changes in mechanical axis angle and knee adduction moment with achieving an increase of ≥10 points in the Knee injury and Osteoarthritis Outcome Score (KOOS)4 at 5 years, with and without adjusting for covariates. Gait data were also compared to existing data from healthy controls.

RESULTS

Mean 5-year changes (95% confidence interval (CI)) were: KOOS4: +14.2 (10.8, 17.6); mechanical axis angle: +8.21° (7.58, 8.83); knee adduction moment: -1.49 %BW*Ht (-1.35, -1.63). The postoperative knee adduction moments were typically lower than values for healthy controls. When divided into quartiles, although all strata improved significantly, patients with reductions in knee adduction moment of 1.14-1.74 %BW*Ht (neither largest nor smallest changes) had highest 5-year KOOS4 scores. The 6-month change in knee adduction moment (odds ratios (OR) = 0.38; 95% CI: 0.22, 0.67), preoperative KOOS4 (OR = 0.96; 95% CI: 0.94, 0.99) and preoperative medial tibiofemoral narrowing grade (OR = 0.62; 95% CI: 0.37, 1.00) were negatively associated with having a 5-year clinically important improvement (C-statistic = 0.70).

CONCLUSIONS

Substantial improvements in biomechanical risk factors and patient-reported outcomes are observed 5 years after medial opening wedge HTO. The surgery-induced change in load distribution during walking is significantly associated with long-term clinically important improvement.

Subchondral tibial bone texture predicts the incidence of radiographic knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVES

To evaluate whether trabecular bone texture (TBT) parameters measured on computed radiographs (CR) could predict the onset of radiographic knee osteoarthritis (OA).

MATERIALS AND METHODS

Subjects from the Osteoarthritis Initiative (OAI) with no sign of radiographic OA at baseline were included. Cases that developed either a global radiographic OA defined by the Kellgren-Lawrence (KL) scale, a joint space narrowing (JSN) or tibial osteophytes (TOS) were compared with the controls with no changes after 48 months of follow-up. Baseline bilateral fixed flexion CR were analyzed using a fractal method to characterize the local variations. The prediction was explored using logistic regression models evaluated by the area under the receiver operating characteristic curves (AUC).

RESULTS

From the 344 knees, 79 (23%) developed radiographic OA after 48 months, 44 (13%) developed progressive JSN and 59 (17%) developed osteophytes. Neither age, gender and BMI, nor their combination predicted poorer KL (AUC 0.57), JSN or TOS (AUC 0.59) scores. The inclusion of the TBT parameters in the models improved the global prediction results for KL (AUC 0.69), JSN (AUC 0.73) and TOS (AUC 0.71) scores.

CONCLUSIONS

Several differences were found between the models predictive of three different outcomes (KL, JSN and TOS), indicating different underlying mechanisms. These results suggest that TBT parameters assessed when radiographic signs are not yet apparent on radiographs may be useful in predicting the onset of radiological tibiofemoral OA as well as identifying at-risk patients for future clinical trials.

Cartilage and Muscle Cell Fate and Origins during Lizard Tail Regeneration

Introduction

Human cartilage is an avascular tissue with limited capacity for repair. By contrast, certain lizards are capable of musculoskeletal tissue regeneration following tail loss throughout all stages of their lives. This extraordinary ability is the result of a complex process in which a blastema forms and gives rise to the tissues of the regenerate. Blastemal cells have been shown to originate either from dedifferentiated tissues or from existing progenitor cells in various species, but their origin has not been determined in lizards. As reptiles, lizards are the closest relatives to mammals with enhanced regenerative potential, and the origin of blastemal cells has important implications for the regenerative process. Hence, the aim of this study is to determine the cellular origin of regenerated cartilage and muscle tissues in reptiles using the mourning gecko lizard as the regenerative model.

Methods

To trace the fate and differentiation potential of cartilage during tail regeneration, cartilage cells pre-labeled with the fluorescent tracer Dil were injected into lizard tails, and the contribution of cartilage cells to regenerated tail tissues was assessed by histologic examination at 7, 14, and 21 days post-tail amputation. The contribution of muscle cells to regenerated tail tissues was evaluated using muscle creatine kinase promoter-driven Cre recombinase in conjunction with the Cre-responsive green-to-red fluorescence shift construct CreStoplight. 21 days after amputation, tail tissues were analyzed by histology for red fluorescent protein (RFP)-positive cells.

Results

At 7 days post-amputation, Dil-labeled cartilage cells localized to the subapical space contributing to the blastema. At 14 and 21 days post-amputation, Dil-labeled cells remained in the subapical space and colocalized with Collagen type II (Col2) staining in the cartilage tube and myosin heavy chain (MHC) staining in regenerated muscle. Lineage tracing of myocytes showed colocalization of RFP with Col2 and MHC in differentiated tissues at 21 days post-amputation.

Conclusion

This study demonstrates that differentiated cartilage cells contribute to both regenerated muscle and cartilage tissues following tail loss, and in turn, differentiated muscle cells contribute to both tissue types as well. These findings suggest that dedifferentiation and/or transdifferentiation are at least partially responsible for the regenerative outcome in the mourning gecko.

Rationale and design of the Staying Positive with Arthritis (SPA) Study: A randomized controlled trial testing the impact of a positive psychology intervention on racial disparities in pain

Knee osteoarthritis is a painful, disabling condition that disproportionately affects African Americans. Existing arthritis treatments yield small to moderate improvements in pain and have not been effective at reducing racial disparities in the management of pain. The biopsychosocial model of pain and evidence from the positive psychology literature suggest that increasing positive psychological skills (e.g., gratitude, kindness) could improve pain and functioning and reduce disparities in osteoarthritis pain management. Activities to cultivate positive psychological skills have been developed and validated; however, they have not been tested in patients with osteoarthritis, their effects on racial differences in health outcomes have not been examined, and evidence of their effects on health outcomes in patients with other chronic illnesses is of limited quality. In this article we describe the rationale and design of Staying Positive with Arthritis (SPA) study, a randomized controlled trial in which 180 African American and 180 White primary care patients with chronic pain from knee osteoarthritis will be randomized to a 6-week program of either positive skill-building activities or neutral control activities. The primary outcomes will be self-reported pain and functioning as measured by the WOMAC Osteoarthritis Index. We will assess these primary outcomes and potential, exploratory psychosocial mediating variables at an in-person baseline visit and by telephone at 1, 3, and 6months following completion of the assigned program. If effective, the SPA program would be a novel, theoretically-informed psychosocial intervention to improve quality and equity of care in the management of chronic pain from osteoarthritis.

Osteoarthritis: Models for appropriate care across the disease continuum

Osteoarthritis (OA) is a leading cause of pain and disability worldwide. Despite the existence of evidence-based treatments and guidelines, substantial gaps remain in the quality of OA management. There is underutilization of behavioral and rehabilitative strategies to prevent and treat OA as well as a lack of processes to tailor treatment selection according to patient characteristics and preferences. There are emerging efforts in multiple countries to implement models of OA care, particularly focused on improving nonsurgical management. Although these programs vary in content and setting, key lessons learned include the importance of support from all stakeholders, consistent program delivery and tools, a coherent team to run the program, and a defined plan for outcome assessment. Efforts are still needed to develop, deliver, and evaluate models of care across the spectrum of OA, from prevention through end-stage disease, in order to improve care for this highly prevalent global condition.

The Disease-Modifying Effects of Hyaluronan in the Osteoarthritic Disease State

Hyaluronic acid (HA) has been a treatment modality for patients with knee osteoarthritis (OA) for many years now. Since HA was first introduced for the treatment of painful knee OA, much has been elucidated regarding both the etiology of this disease and the mechanisms by which HA may mitigate joint pain and tissue destruction. The objectives of this article are to (1) describe the etiology and pathophysiology of OA including both what is known about the genetics and biochemistry, (2) describe the role of HA on disease progression, (3) detail the antinociceptive and anti-inflammatory actions of HA in OA, and (4) present evidence of disease-modifying effects of HA in the preservation and restoration of the extracellular matrix. These data support that HA is not only just a simple device used for viscosupplementation but also a biologically active molecule that can affect the physiology of articular cartilage.

Distribution and Drivers of Average Direct Cost of Osteoarthritis in Canada From 2003 to 2010

OBJECTIVE

To estimate the distribution and drivers of the average direct cost of osteoarthritis (OA) in Canada using a population-based health microsimulation model of OA from 2003 to 2010.

METHODS

We used a previously published microsimulation model to estimate the distribution of average cost of OA across different cost components and OA stages. OA stages were defined according to the patient flow within the health care system. Cost components associated with pharmacologic and nonpharmacologic treatments, physician visits, and hospitalization were included. Scenario analysis was performed to evaluate average cost drivers from 2003 to 2010.

RESULTS

During the study period, the OA population size grew from 2.9 to 3.6 million, while the average cost increased from $577 to $811 (Canadian) per patient per year. The highest increase in share of cost components was for total joint replacement (TJR) surgery (24% to 32%). The highest average cost was incurred by patients in stage 4 (during and after revision surgery), while around 80% of OA patients were in stage 1 (OA diagnosed but has not visited an orthopedic surgeon). Increase in the proportion of OA patients receiving TJR surgeries (34%) and price inflation (29%) were the most significant drivers of average cost.

CONCLUSION

The average cost of OA has been increasing during the study period mostly due to an increase in the proportion of patients receiving TJR surgeries and price inflation. The distribution of average cost of OA across disease stages needs to be considered when designing policies targeting specific aspects of OA care.

Randomized Controlled Trial of an Educational Intervention Using an Online Risk Calculator for Knee Osteoarthritis: Effect on Risk Perception

OBJECTIVE

Young adults, in general, are not aware of their risk of knee osteoarthritis (OA). Understanding risk and risk factors is critical to knee OA prevention. We tested the efficacy of a personalized risk calculator on accuracy of knee OA risk perception and willingness to change behaviors associated with knee OA risk factors.

METHODS

We conducted a randomized controlled trial of 375 subjects recruited using Amazon Mechanical Turk. Subjects were randomized to either use a personalized risk calculator based on demographic and risk-factor information (intervention), or to view general OA risk information (control). At baseline and after the intervention, subjects estimated their 10-year and lifetime risk of knee OA and responded to contemplation ladders measuring willingness to change diet, exercise, or weight-control behaviors.

RESULTS

Subjects in both arms had an estimated 3.6% 10-year and 25.3% lifetime chance of developing symptomatic knee OA. Both arms greatly overestimated knee OA risk at baseline, estimating a 10-year risk of 26.1% and a lifetime risk of 47.8%. After the intervention, risk calculator subjects' perceived 10-year risk decreased by 12.9 percentage points to 12.5% and perceived lifetime risk decreased by 19.5 percentage points to 28.1%. Control subjects' perceived risks remained unchanged. Risk calculator subjects were more likely to move to an action stage on the exercise contemplation ladder (relative risk 2.1). There was no difference between the groups for diet or weight-control ladders.

CONCLUSION

The risk calculator is a useful intervention for knee OA education and may motivate some exercise-related behavioral change.

Clinical Validation of Pain Management Manipulative Therapy for Knee Osteoarthritis With the Squeeze-Hold Technique: A Case Series

OBJECTIVE

The purpose of this case series was to describe the short-term and long-term clinical effects of a manual technique for treating osteoarthritis (OA) knee pain.

METHODS

This study measured of the immediate effect and long-term effect by using a case series of different groups of subjects. Knee OA and activity restriction in patients were evaluated by using the Kellgren-Lawrence (K/L) Grading Scale and the Japanese Knee Osteoarthritis Measure (JKOM) index. In the intervention, lower limb muscles were squeezed by hand for 20 seconds. Each squeeze was performed for both lower limbs. Passive range-of-motion (ROM) exercise was performed on the knee joint. In one set of cases, immediate effects were measured after a one-time treatment with pretreatment and posttreatment outcome measures. Eleven people with knee OA participated in the study. On a visual analogue scale (VAS) for pain, muscle stiffness, and muscular hemodynamics for estimation of muscle blood flow were recorded before and after the squeeze-hold treatment. In another set of cases, the treatment was given to all patients once a week for 6 months, and long-term effects were measured. Data on 5 subjects with knee OA were collected for 6 months after initial treatment. The VAS for pain and JKOM were recorded every month for 6 months.

RESULTS

For immediate effects, the VAS was 69 ± 21 mm before treatment and 26 ± 22 mm after treatment. Muscle stiffness was 8.8 ± 3.6 (absolute number) before treatment and 3.5 ± 2.1 after treatment. Tissue (muscle) oxygen saturation was 60.1 ± 5.7% before treatment and 65.3 ± 4.8% after treatment. Total hemoglobin was 24.3 ± 3.3 (absolute number) before treatment and 25 ± 2.3 after treatment. A tendency for reduction in OA knee pain and muscle stiffness was observed, and a tendency for increase was observed in the blood flow in the muscle. For long-term effects in all 5 participants (any K/L grade, any JKOM score), OA knee pain and JKOM score improved gradually through 6 months.

CONCLUSIONS

The participants in this case series showed improvement in pain and function. These findings indicate the feasibility of a larger study on the squeeze-hold intervention for OA knee pain.

Association of Early Outpatient Rehabilitation With Health Service Utilization in Managing Medicare Beneficiaries With Nontraumatic Knee Pain: Retrospective Cohort Study

BACKGROUND

Nontraumatic knee pain (NTKP) is highly prevalent in adults 65 years of age and older. Evidence-based guidelines recommend early use of rehabilitation; however, there is limited information comparing differences in health care utilization when rehabilitation is included in the management of NTKP.

OBJECTIVES

To describe the overall health care utilization associated with the management of NTKP; estimate the proportion of people who receive outpatient rehabilitation services; and evaluate the timing of outpatient rehabilitation and its association with other health care utilization.

DESIGN

Rretrospective cohort study was conducted using a random 10% sample of 2009-2010 Medicare claims. The sample included 52,504 beneficiaries presenting within the ambulatory setting for management of NTKP.

METHODS

Exposure to outpatient rehabilitative services following the NTKP index ambulatory visit was defined as 1) no rehabilitation; 2) early rehabilitation (1-15 days); 3) intermediate rehabilitation (16-120 days); and 4) late rehabilitation (>120 days). Logistic regression models were fit to analyze the association of rehabilitation timing with narcotic analgesic use, utilization of nonsurgical invasive procedure, and knee surgery during a 12-month follow-up period.

RESULTS

Only 11.1% of beneficiaries were exposed to outpatient rehabilitation services. The likelihood of using narcotics, nonsurgical invasive procedures, or surgery was significantly less (adjusted odds ratios; 0.67, 0.50, 0.58, respectively) for those who received early rehabilitation when compared to no rehabilitation. The exposure-outcome relationships were reversed in the intermediate and late rehabilitation cohorts.

LIMITATIONS

This was an observational study, and residual confounding could affect the observed relationships. Therefore, definitive conclusions regarding the causal effect of rehabilitation exposure and reduced utilization of more aggressive interventions cannot be determined at this time.

CONCLUSIONS

Early referral for outpatient rehabilitation may reduce the utilization of health services that carry greater risks or costs in those with NTKP.

Impact of Preoperative Opioid Use on Total Knee Arthroplasty Outcomes

BACKGROUND

There is growing concern about the use of opioids prior to total knee arthroplasty (TKA), and research has suggested that preoperative opioid use may lead to worse pain outcomes following surgery. We evaluated the pain relief achieved by TKA in patients who had and those who had not used opioids use before the procedure.

METHODS

We augmented data from a prospective cohort study of TKA outcomes with opioid-use data abstracted from medical records. We collected patient-reported outcomes and demographic data before and 6 months after TKA. We used the Pain Catastrophizing Scale and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to quantify the pain experiences of patients treated with TKA who had had a baseline score of ≥20 on the WOMAC pain scale (a 0 to 100-point scale, with 100 being the worst score), who provided follow-up data, and who had not had another surgical procedure within the 2 years prior to TKA. We built a propensity score for preoperative opioid use based on the Pain Catastrophizing Scale score, comorbidities, and baseline pain. We used a general linear model, adjusting for the propensity score and baseline pain, to compare the change in the WOMAC pain score 6 months after TKA between persons who had and those who had not used opioids before TKA.

RESULTS

The cohort included 156 patients with a mean age of 65.7 years (standard deviation [SD] = 8.2 years) and a mean body mass index (BMI) of 31.1 kg/m (SD = 6.1 kg/m); 62.2% were female. Preoperatively, 36 patients (23%) had had at least 1 opioid prescription. The mean baseline WOMAC pain score was 43.0 points (SD = 12.8) for the group that had not used opioids before TKA and 46.9 points (SD = 15.7) for those who had used opioids (p = 0.12). The mean preoperative Pain Catastrophizing Scale score was greater among opioid users (15.5 compared with 10.7 points among non-users, p = 0.006). Adjusted analyses showed that the opioid group had a mean 6-month reduction in the WOMAC pain score of 27.0 points (95% confidence interval [CI] = 22.7 to 31.3) compared with 33.6 points (95% CI = 31.4 to 35.9) in the non-opioid group (p = 0.008).

CONCLUSIONS

Patients who used opioids prior to TKA obtained less pain relief from the operation. Clinicians should consider limiting pre-TKA opioid prescriptions to optimize the benefits of TKA.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial

IMPORTANCE

Synovitis is common and is associated with progression of structural characteristics of knee osteoarthritis. Intra-articular corticosteroids could reduce cartilage damage associated with synovitis but might have adverse effects on cartilage and periarticular bone.

OBJECTIVE

To determine the effects of intra-articular injection of 40 mg of triamcinolone acetonide every 3 months on progression of cartilage loss and knee pain.

DESIGN, SETTING, AND PARTICIPANTS

Two-year, randomized, placebo-controlled, double-blind trial of intra-articular triamcinolone vs saline for symptomatic knee osteoarthritis with ultrasonic features of synovitis in 140 patients. Mixed-effects regression models with a random intercept were used to analyze the longitudinal repeated outcome measures. Patients fulfilling the American College of Rheumatology criteria for symptomatic knee osteoarthritis, Kellgren-Lawrence grades 2 or 3, were enrolled at Tufts Medical Center beginning February 11, 2013; all patients completed the study by January 1, 2015.

INTERVENTIONS

Intra-articular triamcinolone (n = 70) or saline (n = 70) every 12 weeks for 2 years.

MAIN OUTCOMES AND MEASURES

Annual knee magnetic resonance imaging for quantitative evaluation of cartilage volume (minimal clinically important difference not yet defined), and Western Ontario and McMaster Universities Osteoarthritis index collected every 3 months (Likert pain subscale range, 0 [no pain] to 20 [extreme pain]; minimal clinically important improvement, 3.94).

RESULTS

Among 140 randomized patients (mean age, 58 [SD, 8] years, 75 women [54%]), 119 (85%) completed the study. Intra-articular triamcinolone resulted in significantly greater cartilage volume loss than did saline for a mean change in index compartment cartilage thickness of -0.21 mm vs -0.10 mm (between-group difference, -0.11 mm; 95% CI, -0.20 to -0.03 mm); and no significant difference in pain (-1.2 vs -1.9; between-group difference, -0.6; 95% CI, -1.6 to 0.3). The saline group had 3 treatment-related adverse events compared with 5 in the triamcinolone group and had a small increase in hemoglobin A1c levels (between-group difference, -0.2%; 95% CI, -0.5% to -0.007%).

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic knee osteoarthritis, 2 years of intra-articular triamcinolone, compared with intra-articular saline, resulted in significantly greater cartilage volume loss and no significant difference in knee pain. These findings do not support this treatment for patients with symptomatic knee osteoarthritis.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01230424.

Long-term clinical benefit and cost-effectiveness of an 8-week multimodal knee osteoarthritis management program incorporating intra-articular sodium hyaluronate (Hyalgan®) injections

Background

Given the poor long-term effectiveness of focused nonsurgical knee osteoarthritis (OA) treatments, alternative therapies are needed for patients who have unsuccessfully exhausted nonsurgical options.

Methods

A telephone interview was conducted in patients who participated in a single 8-week multimodal knee OA treatment program (mean follow-up: 3.7 years, range: 2.7–4.9 years). The program consisted of five intra-articular knee injections of sodium hyaluronate (Hyalgan^®), with each injection given 1 week apart, structured physical therapy, knee bracing, and patient education. Clinical outcomes included knee pain severity, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscores, current medication use, and history of total knee arthroplasty. Base-case, subgroup, and sensitivity analyses were conducted to determine the incremental cost-effectiveness ratio (ICER) of the treatment program with comparisons made to historical literature controls undergoing usual care.

Results

A total of 218 patients (54%) provided long-term follow-up data. Knee pain severity decreased 60% and WOMAC subscores decreased 33%–42% compared to baseline (all p<0.001). Total knee arthroplasty was performed in 22.8% (81/356) of knees during followup. The treatment program was highly cost-effective compared to usual care with a base-case ICER of $6,000 per quality-adjusted life year (QALY). Results of subgroup analyses, one-way deterministic sensitivity analyses, and second-order probabilistic sensitivity analyses resulted in ICERs ranging from $3,996 to $10,493 per QALY. The percentage of simulations with an ICER below willingness-to-pay limits was 97.2%, 98.9%, and 99.4% for the $50,000, $100,000, and $150,000 per QALY thresholds, respectively.

Conclusion

Participation in a single 8-week knee OA treatment program, which included one cycle of five intra-articular knee injections of sodium hyaluronate given at weekly intervals, is highly cost-effective and provides clinically meaningful reductions in patient symptoms that are maintained over 3.7 years mean follow-up.

The Cost-Effectiveness of Dual Mobility Implants for Primary Total Hip Arthroplasty: A Computer-Based Cost-Utility Model

BACKGROUND

Dislocation remains a clinically important problem following primary total hip arthroplasty, and it is a common reason for revision total hip arthroplasty. Dual mobility (DM) implants decrease the risk of dislocation but can be more expensive than conventional implants and have idiosyncratic failure mechanisms. The purpose of this study was to investigate the cost-effectiveness of DM implants compared with conventional bearings for primary total hip arthroplasty.

METHODS

Markov model analysis was conducted from the societal perspective with use of direct and indirect costs. Costs, expressed in 2013 U.S. dollars, were derived from the literature, the National Inpatient Sample, and the Centers for Medicare & Medicaid Services. Effectiveness was expressed in quality-adjusted life years (QALYs). The model was populated with health state utilities and state transition probabilities derived from previously published literature. The analysis was performed for a patient's lifetime, and costs and effectiveness were discounted at 3% annually. The principal outcome was the incremental cost-effectiveness ratio (ICER), with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to explore relevant uncertainty.

RESULTS

In the base case, DM total hip arthroplasty showed absolute dominance over conventional total hip arthroplasty, with lower accrued costs ($39,008 versus $40,031 U.S. dollars) and higher accrued utility (13.18 versus 13.13 QALYs) indicating cost-savings. DM total hip arthroplasty ceased being cost-saving when its implant costs exceeded those of conventional total hip arthroplasty by $1,023, and the cost-effectiveness threshold for DM implants was $5,287 greater than that for conventional implants. DM was not cost-effective when the annualized incremental probability of revision from any unforeseen failure mechanism or mechanisms exceeded 0.29%. The probability of intraprosthetic dislocation exerted the most influence on model results.

CONCLUSIONS

This model determined that, compared with conventional bearings, DM implants can be cost-saving for routine primary total hip arthroplasty, from the societal perspective, if newer-generation DM implants meet specific economic and clinical benchmarks. The differences between these thresholds and the performance of other contemporary bearings were frequently quite narrow. The results have potential application to the postmarket surveillance of newer-generation DM components.

LEVEL OF EVIDENCE

Economic and decision analysis Level III. See Instructions for Authors for a complete description of levels of evidence.

Cartilage Oligomeric Matrix Protein Levels in Synovial Fluid in Patients With Primary Knee Osteoarthritis And Healthy Controls: A Preliminary Comparative Analysis With Serum Cartilage Oligomeric Matrix Protein

Objectives

This study aims (i) to compare synovial fluid and serum cartilage oligomeric matrix protein levels in patients with primary knee osteoarthritis and healthy controls, (ii) compare variations of synovial fluid and serum cartilage oligomeric matrix protein levels according to sex, Kellgren-Lawrence grades, and daytime sampling, and (iii) correlate the synovial fluid and serum cartilage oligomeric matrix protein levels with age, severity of disease, and daytime sampling.

Patients and methods

One hundred and twenty-four individuals (44 males, 80 females; median age 66 years; range 42 to 87 years) were diagnosed with primary knee osteoarthritis according to the American College of Rheumatology guidelines. Additionally, 105 healthy healthy individuals (49 males, 56 females; median age 50 years; range 30 to 75 years) were included as the control group. For both groups, a thorough clinical history and physical examination were performed. Moreover, weight-bearing anteroposterior and lateral bending 30 degrees knee X-rays were collected. Cartilage oligomeric matrix protein in serum and synovial fluid was measured by enzyme-linked immunosorbent assay.

Results

Total synovial fluid cartilage oligomeric matrix protein levels were considerably higher than total serum levels for both groups. Levels of cartilage oligomeric matrix protein in synovial fluid and serum were higher in patients than in controls for both sexes. However, only cartilage oligomeric matrix protein levels in synovial fluid were higher in female patients. The levels of synovial fluid cartilage oligomeric matrix protein were significantly higher when sampling after 12 pm. A positive correlation was found between synovial fluid and serum cartilage oligomeric matrix protein levels, age, and daytime sampling.

Conclusion

These findings may suggest a possible role for synovial fluid and serum cartilage oligomeric matrix protein as a measure for primary knee osteoarthritis. However, more studies need to be performed to address other factors that may influence the levels of cartilage oligomeric matrix protein in synovial fluid and serum.

Impact of total knee replacement practice: cost effectiveness analysis of data from the Osteoarthritis Initiative

Objectives To evaluate the impact of total knee replacement on quality of life in people with knee osteoarthritis and to estimate associated differences in lifetime costs and quality adjusted life years (QALYs) according to use by level of symptoms.Design Marginal structural modeling and cost effectiveness analysis based on lifetime predictions for total knee replacement and death from population based cohort data.Setting Data from two studies-Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis Study (MOST)-within the US health system.Participants 4498 participants with or at high risk for knee osteoarthritis aged 45-79 from the OAI with no previous knee replacement (confirmed by baseline radiography) followed up for nine years. Validation cohort comprised 2907 patients from MOST with two year follow-up.Intervention Scenarios ranging from current practice, defined as total knee replacement practice as performed in the OAI (with procedural rates estimated by a prediction model), to practice limited to patients with severe symptoms to no surgery.Main outcome measures Generic (SF-12) and osteoarthritis specific quality of life measured over 96 months, model based QALYs, costs, and incremental cost effectiveness ratios over a lifetime horizon.Results In the OAI, total knee replacement showed improvements in quality of life with small absolute changes when averaged across levels of confounding variables: 1.70 (95% uncertainty interval 0.26 to 3.57) for SF-12 physical component summary (PCS); -10.69 (-13.39 to -8.01) for Western Ontario and McMaster Universities arthritis index (WOMAC); and 9.16 (6.35 to 12.49) for knee injury and osteoarthritis outcome score (KOOS) quality of life subscale. These improvements became larger with decreasing functional status at baseline. Provision of total knee replacement to patients with SF-12 PCS scores <35 was the optimal scenario given a cost effectiveness threshold of $200 000/QALY, with cost savings of $6974 ($5789 to $8269) and a minimal loss of 0.008 (-0.056 to 0.043) QALYs compared with current practice. These findings were reproduced among patients with knee osteoarthritis from the MOST cohort and were robust against various scenarios including increased rates of total knee replacement and mortality and inclusion of non-healthcare costs but were sensitive to increased deterioration in quality of life without surgery. In a threshold analysis, total knee replacement would become cost effective in patients with SF-12 PCS scores ≤40 if the associated hospital admission costs fell below $14 000 given a cost effectiveness threshold of $200 000/QALY.Conclusion Current practice of total knee replacement as performed in a recent US cohort of patients with knee osteoarthritis had minimal effects on quality of life and QALYs at the group level. If the procedure were restricted to more severely affected patients, its effectiveness would rise, with practice becoming economically more attractive than its current use.

New Drug Treatments for Osteoarthritis: What Is on the Horizon?

Osteoarthritis (OA) is the most common form of arthritis, yet has historically lagged far behind rheumatoid arthritis in terms of drug development. Despite the many challenges presented by clinical trials in OA, improvements in our understanding of disease pathogenesis and a move to treat pain, as well as underlying disease process, mean there are now many new pharmacological therapies currently in various stages of clinical trials. The medical need for these therapies and the evidence for recent tissue and molecular targets are reviewed. Current therapeutic examples in each area are discussed, including both novel therapeutics and existing agents which may be repurposed from other disease areas. Some challenges remain, but opportunities for improving symptoms and disease process in OA in the clinic with new pharmacological agents would appear to be on the close horizon.

New Drug Treatments for Osteoarthritis: What is on the Horizon?

Osteoarthritis (OA) is the most common form of arthritis, yet has historically lagged far behind rheumatoid arthritis in terms of drug development. Despite the many challenges presented by clinical trials in OA, improvements in our understanding of disease pathogenesis and a move to treat pain, as well as underlying disease process, mean there are now many new pharmacological therapies currently in various stages of clinical trials. The medical need for these therapies and the evidence for recent tissue and molecular targets are reviewed. Current therapeutic examples in each area are discussed, including both novel therapeutics and existing agents which may be repurposed from other disease areas. Some challenges remain, but opportunities for improving symptoms and disease process in OA in the clinic with new pharmacological agents would appear to be on the close horizon.

Cost-Effectiveness of Tramadol and Oxycodone in the Treatment of Knee Osteoarthritis

OBJECTIVE

To evaluate the cost-effectiveness of incorporating tramadol or oxycodone into knee osteoarthritis (OA) treatment.

METHODS

We used the Osteoarthritis Policy Model to evaluate long-term clinical and economic outcomes of knee OA patients with a mean age of 60 years with persistent pain despite conservative treatment. We evaluated 3 strategies: opioid-sparing (OS), tramadol (T), and tramadol followed by oxycodone (T+O). We obtained estimates of pain reduction and toxicity from published literature and annual costs for tramadol ($600) and oxycodone ($2,300) from Red Book Online. Based on published data, in the base case, we assumed a 10% reduction in total knee arthroplasty (TKA) effectiveness in opioid-based strategies. Outcomes included quality-adjusted life years (QALYs), lifetime cost, and incremental cost-effectiveness ratios (ICERs) and were discounted at 3% per year.

RESULTS

In the base case, T and T+O strategies delayed TKA by 7 and 9 years, respectively, and led to reduction in TKA utilization by 4% and 10%, respectively. Both opioid-based strategies increased cost and decreased QALYs compared to the OS strategy. Tramadol's ICER was highly sensitive to its effect on TKA outcomes. Reduction in TKA effectiveness by 5% (compared to base case 10%) resulted in an ICER for the T strategy of $110,600 per QALY; with no reduction in TKA effectiveness, the ICER was $26,900 per QALY. When TKA was not considered a treatment option, the ICER for T was $39,600 per QALY.

CONCLUSION

Opioids do not appear to be cost-effective in OA patients without comorbidities, principally because of their negative impact on pain relief after TKA. The influence of opioids on TKA outcomes should be a research priority.

Regenerative Engineering for Knee Osteoarthritis Treatment: Biomaterials and Cell-Based Technologies

Knee osteoarthritis (OA) is the most common form of arthritis worldwide. The incidence of this disease is rising and its treatment poses an economic burden. Two early targets of knee OA treatment include the predominant symptom of pain, and cartilage damage in the knee joint. Current treatments have been beneficial in treating the disease but none is as effective as total knee arthroplasty (TKA). However, while TKA is an end-stage solution of the disease, it is an invasive and expensive procedure. Therefore, innovative regenerative engineering strategies should be established as these could defer or annul the need for a TKA. Several biomaterial and cell-based therapies are currently in development and have shown early promise in both preclinical and clinical studies. The use of advanced biomaterials and stem cells independently or in conjunction to treat knee OA could potentially reduce pain and regenerate focal articular cartilage damage. In this review, we discuss the pathogenesis of pain and cartilage damage in knee OA and explore novel treatment options currently being studied, along with some of their limitations.

Productivity costs of work loss associated with osteoarthritis in Canada from 2010 to 2031

OBJECTIVE

To estimate and project the productivity costs of work loss (PCWL) associated with osteoarthritis (OA) in Canada using the Population Health Model (POHEM).

DESIGN

We integrated an employment module based on 2006 Canadian Census into the previously developed microsimulation model of OA. The Canadian Community Health Survey (CCHS) Cycle 2.1 with an OA sample aged 25-64 (n = 7067) was used to calibrate the results of the employment module and to estimate the fraction of non-employment associated with OA. Probabilities of non-employment together with attributable fractions were then implemented in POHEM to estimate PCWL associated with OA from 2010 to 2031.

RESULTS

Among the OA population, 44.4% and 59.4% of non-employment due to illness was associated with OA for those not working full-year and part-year, respectively. According to POHEM projections, the size of the working age population with OA increased from 1.5 million in 2010 to 1.7 million in 2031. The PCWL associated with OA increased from $12 billion to $17.5 billion in constant 2008 Canadian dollars. Around 38% of this increase was due to the increase in OA prevalence and changes in demographics, while the rest was due to increase in real wage growth. Male and female OA patients between 55 and 64 years of age had the highest total projected PCWL, respectively.

CONCLUSIONS

The total PCWL associated with OA in Canada is estimated to be substantial and increasing in future years. Results of this study could be used to inform policies aiming to increase employment sustainability among individuals with OA.

The Role of Aging in the Development of Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis and a significant cause of pain and disability in older adults. Among the risk factors for OA, age is the most prominent. This review will discuss the relationship between aging and the development of OA, with a particular focus on mechanisms relevant to cartilage degeneration and the role of excessive levels of reactive oxygen species. Rather than just causing random oxidative damage, an increase in reactive oxygen species that leads to oxidative stress disrupts specific cell signaling pathways. This disruption in cell signaling affects the ability to maintain the cartilage extracellular matrix and eventually causes cell death. By understanding the specific cell signaling pathways that lead to OA through altered redox signaling, novel targets will be discovered that will be an advance over the current non-targeted anti-oxidant approach that has not been successful in treating chronic diseases of aging such as OA.

Potential Impact of Biologically Derived Hyaluronic Acid on Quality of Life in Patients with Knee Osteoarthritis in the United States

INTRODUCTION

Knee osteoarthritis is one of the leading causes of disability in the world. Intra-articular hyaluronic acid (IA-HA) is a treatment modality that provides a minimally invasive treatment option for the management of osteoarthritis-related symptoms. This study examined the current and potential economic impact of using a biologically derived, high molecular weight hyaluronic acid preparation (Euflexxa) on the US population for the management of knee osteoarthritis.

METHODS

A model was developed to estimate the total number of patients with symptomatic knee osteoarthritis in the US in 2015, distributed by Kellgren-Lawrence (K-L) grade, and the number of people living with total knee arthroplasty (TKA). The potential utility of Euflexxa was applied to this model population to determine the current and potential impact of the treatment as the total number of quality adjusted life years (QALY) saved within the US population.

RESULTS

There are approximately 12 million people currently suffering from symptomatic knee osteoarthritis in the US, and approximately 5 million living with TKA. It was estimated that, with a target treatment group of K-L grades 2-3, there are approximately 4 million patients eligible for treatment with a high molecular weight intra-articular hyaluronic acid injection. With current use, it is estimated that Euflexxa can save 36,730 QALY/year among the US population, and has the potential to save an additional 369,181 QALY/year if used by all eligible patients.

CONCLUSIONS

This study demonstrates that more widely used, biologically derived, high molecular weight IA-HAs, such as Euflexxa, have the potential to save a substantial number of QALYs among the US population with symptomatic knee osteoarthritis.

FUNDING

Ferring Pharmaceuticals Inc.

The quality-of-life burden of knee osteoarthritis in New Zealand adults: A model-based evaluation

BACKGROUND

Knee osteoarthritis is a leading global cause of health-related quality of life loss. The aim of this project was to quantify health losses arising from knee osteoarthritis in New Zealand (NZ) in terms of quality-adjusted life years (QALYs) lost.

METHODS

The Osteoarthritis Policy Model (OAPol), a validated Monte Carlo computer simulation model, was used to estimate QALYs lost due to knee osteoarthritis in the NZ adult population aged 40-84 over their lifetimes from the base year of 2006 until death. Data were from the NZ Health Survey, NZ Burden of Diseases, NZ Census, and relevant literature. QALYs were derived from NZ EQ-5D value set 2. Sensitivity to health state valuation, disease and pain prevalence were assessed in secondary analyses.

RESULTS

Based on NZ EQ-5D health state valuations, mean health losses due to knee osteoarthritis over people's lifetimes in NZ are 3.44 QALYs per person, corresponding to 467,240 QALYs across the adult population. Average estimated per person QALY losses are higher for non-Māori females (3.55) than Māori females (3.38), and higher for non-Māori males (3.34) than Māori males (2.60). The proportion of QALYs lost out of the total quality-adjusted life expectancy for those without knee osteoarthritis is similar across all subgroups, ranging from 20 to 23 percent.

CONCLUSIONS

At both the individual and population levels, knee osteoarthritis is responsible for large lifetime QALY losses. QALY losses are higher for females than males due to greater prevalence of knee osteoarthritis and higher life expectancy, and lower for Māori than non-Māori due to lower life expectancy. Large health gains are potentially realisable from public health and policy measures aimed at decreasing incidence, progression, pain, and disability of osteoarthritis.

Projecting Lifetime Risk of Symptomatic Knee Osteoarthritis and Total Knee Replacement in Individuals Sustaining a Complete Anterior Cruciate Ligament Tear in Early Adulthood

OBJECTIVE

To estimate the lifetime risk of knee osteoarthritis (OA) and total knee replacement (TKR) in persons sustaining anterior cruciate ligament (ACL) tear by age 25 years.

METHODS

We used the Osteoarthritis Policy Model to project the cumulative incidence of symptomatic knee OA requiring TKR in varying situations: no prevalent or incident injury; isolated ACL tear, surgically treated; isolated ACL tear, nonoperatively treated; or a prevalent history or surgically treated ACL and meniscal tear (MT). We estimated MT prevalence and incidence and increased risk of knee OA associated with ACL injury and MT from published literature. We conducted a range of sensitivity analyses to examine the impact of uncertainty in input parameters.

RESULTS

Estimated lifetime risk of symptomatic knee OA was 34% for the cohort with ACL injury and MT, compared to 14% for the no-injury cohort. ACL injury without MT was associated with a lifetime risk of knee OA between 16% and 17%, depending on ACL treatment modality. Estimated lifetime risk of TKR ranged from 6% in the no-injury cohort to 22% for the ACL injury and MT cohort. Subjects in the ACL injury and MT cohort developed OA approximately 1.5 years earlier (55.7 versus 57.1) and underwent TKR approximately 2 years earlier (66 versus 68) than the cohort without knee injuries.

CONCLUSION

Sustaining ACL injury early in adulthood leads to greater lifetime risk and earlier onset of knee OA and TKR; concomitant MTs compound this risk. These data provide insight into the impact of sustainable injury prevention interventions in young adults.

Effects of short-wave therapy in patients with knee osteoarthritis: a systematic review and meta-analysis

Objective:

To evaluate the efficacy and safety of short-wave therapy with sham or no intervention for the management of patients with knee osteoarthritis.

Methods:

We searched the following databases from their inception up to 26 October 2016: MEDLINE, CENTRAL, EMBASE, Physiotherapy Evidence Database, CINAHL and OpenGrey. Studies included randomized controlled trials compared with a sham or no intervention in patients with knee osteoarthritis. The results were calculated via standardized mean difference (SMD) and risk ratio for continuous variables outcomes as well as dichotomous variables, respectively. Heterogeneity was explored by the I2 test and inverse-variance random effects analysis was applied to all studies.

Results:

Eight trials (542 patients) met the inclusion criteria. The effect of short-wave therapy on pain was found positive (SMD, −0.53; 95% CI, −0.84 to −0.21). The pain subgroup showed that patients received pulse modality achieved clinical improvement (SMD, –0.83; 95% CI, –1.14 to −0.52) and the pain scale in female patients decreased (SMD, −0.53; 95% CI, −0.98 to −0.08). In terms of extensor strength, short-wave therapy was superior to the control group ( p < 0.05, I2 = 0%). There was no significant difference in the physical function (SMD, −0.16; 95% CI, −0.36 to 0.05). For adverse effects, there was no significant difference between the treatment and control group.

Conclusion:

Short-wave therapy is beneficial for relieving pain caused by knee osteoarthritis (the pulse modality seems superior to the continuous modality), and knee extensor muscle combining with isokinetic strength. Function is not improved.